Illuminated aircraft



Jan. 16, 1945.

A. J. DAVIS ILLUMINATED AIRCRAFT Filed Oct. 19,1942

FIG. 5

' INVENTOR Patented Jan. 16, 1945 UNITED STATES PATENT OFFICE ILLUMINATED AIRCRAFT Arthur Davis, Milwaukee, Wis.

Application October 19, 1942, Serial No. 462,539

' 9 Claims. ('01. 250-71) -This invention relates to; improvements in illuminated aircraft.

It is the primary object of the invention to provide without undue heat for the direct illumination of the skin or envelope of an aircraft sur- 5 will develop in previously known devices, excesface, while desirably avoiding any exposure of the sive heat within small space in the aircraft or, "lighting equipment and any impairment of the alternatively, an;excessive amount of resistance acre-dynamic qualities of the aircraft. to move ent o the equipment if p d The objective is to make the aircraft, or some ,teriorly.

selected portion of the aircraft, conspicuously I 10 I also-desire to beable to control the lighting visible either from the air or from the ground as to color, location and operation. or from both points of view, thereby adapting the By the invention herein disclosed, I have invention. for use not onlyin the promotion of solved problemsinvolved in the illumination of safety, but also in-the field of advertising. aircraft both for safety purposes and for adver- In the past, insofar- .as aircraft have been 5 tising, ina manner w i req r s a minim m f illuminated, the illumination has been inadepower, develops little heat, and provides little or quate from a safety standpoint. Incandescent no exposed equipment to reduce the eificiency of lamps have commonlybeen used to illuminate the the aerofoils. The invention will be more speso-called flying lights of red and green carried ciflcally understood and other objectives appreat the wing tips. Such flying lights, because of .20 ciated by those skilled in the art upon examinatheir slight area and low power, have not been tion of the following-disclosure. sufficiently conspicuous and, particularly from In t e d a 2 the point of view of a higher aircraft against a Fig. 1 is a fragmentary bottom plan view of a background of such numerous night lights as are portion of an aeroplane wing embodying my infound in the vicinityof cities, the aircraft flying vention. lights have been perceptible only with difliculty. Fig. 2 is a detail view of the wing in cross'sec- Several considerations have precluded the use tion on the line 2-2of Fi of more conspicuous flyinglights heretofore. In Fig.3 is a bottom plan V ew On a enlarged the first place, the illumination of large areas scale of the rear end portion of the fuselage of an has involved considerable weightof equipment aeroplane embodying my invention. and the power requirements for the energization i 4 s a eta V w a St ll further enof incandescent bulbs of such high candle power larged scale showing in elevation a bracket such as to be conspicuous in small sizes are excessive a y b s for the p t O t ctivatin from the standpoint of the increasedweight of quipm nt w thi h aerofoil s in r wine ov r battery or generator equipment required. In the a o a With y nt second place, the heat given off by many lights Fig. 5.is a fragmentary bottom plan view of a or lights of high candle power is so great 'as to modifiedembodiment of the invention. make it undesirable to have these housed within Like parts are identified by the same reference the Wing. Moreover, insofar as a lamp is housed characters throughout the several views. within the wing itis not fully visible and it is 40 As is well known in the art, aircraft are condifiicult to provide any window space through ventionally made up of the relatively light skin or which the light is visible. at wide angles without envelope which, in some aeroplanes, is made of I impairing the streamline surfaces of the wing or metal or wood but which, in other airplanes and exposing margins of the wing covering in such in dirigible balloons, is made of fabric or plastic. a manner that they are apt to be torn. In the The skin or envelope of fabric may, in the case of third place, it is very objectionable to have such I heavier than air machines, be stretched over a lights exposed at the outside of the wing because, skeleton framework and in the case of dirigibles when exposed, they introduce a new source of and other balloons, is held distended by pressure air resistance and, ,moreover, become liable to of a gas. The present invention contemplates breakage. v thatregardless of the character of the skin or What has been said as to flying lights is even envelope which provides the actual aerofoil of more serious with regard to lights carried by the aircraft,.such skin or envelope shall itself aircraft for advertising purposes; In order to 'be rendered highly luminous as distinguished make advertisingmaterial clearly legible from the from any, arrangement for hanging luminous bodiesfrom it or mounting luminous bodies withground while the aircraft remains at a safe height above a city, it is necessary to use a rather high degree of illumination involving either a large area of illumination or very substantial power requirements or both. These, in turn,

in it before windows through which such bodies may be viewed. In accordance with the present invention it is the aerofoil surface itself which is the luminous body. I have selected for illustration two different ways for accomplishing this result.

In the construction shown in Figs. 1 to 4 inclusive, the wing 6 and the fuselage I comprise aerofoil surfaces having an, envelope or covering at 8 which is held suspended by the conventional interior framework which includes, inthe case of the wings, interior spars at 9. Upon these spars I mount brackets I (Fig. 2 and Fig. 4) of any,

desired type for the support of any desired form I of a generator II of rays capable of activating fluorescent material. In accordance with the objectives of this invention the generator will preferably be one which will operate at a low'temperature and ordinarily it will generate ult a violet rays, most of which are outside of the visible light spectrum.

The generator shown at I I may constitute a tubular lamp of the gaseous discharge type filled with such gases as the vapors of mercury or argon or both. While'the generators II have been referred to and are frequently referred to as lamps, it will be understood that they are preferablynot used for'direct illumination, or for any illumination in any ordinarily accepted sense.

Such'visible light as issues therefrom is purely incidental to their development of ultra violet rays when connected, as by the wiring indicator 'at I2 (Fig. 1) to any suitable source of high'frequency excitation (not shown). As indicated in Fig. l, a number of the activating tubes may be connected'together to a single source. Fig. 1 illustrates this point by showing a series connection diagrammatically indicated in dotted lines. The activating tubes are within the wing. On the exterior surface of the wing covering 8 which constitutes the'act'ual aerofoil surfaceI provide a coating in the nature of paint which comprises or contains a material highly luminescent when activated by rays such as those given off by the tubes I I. This coating may cover whether it continues to give off light after activation ceases. Numerous materials of both types are widely known, including luminous zinc sulfide, calcium sulphide, platino-cyan-id of barium, silicate of zinc, calcium tungstate, anthracene, etc. All such material, whether it fluoresces or erator may control the portion of the aircraft which is rendered luminous.

Since different substances fluoresce and phosphoresce in different colors, when activated, it is possible to obtain any color scheme desired. One entire wing of an aeroplane may be made to glow with red light, while the other wing glows with green light. For military aviation it may be desirable to limit the illumination either to the upperor the lower surfaces, according to circumstances, so that the plane thus treated will be conspicuous from one direction and not from another.

The constructions illustrated in Figs. 1 and 4 inclusivepresuppose that the aerofoil sheath or envelope is of such a character that it can be penetrated by the activating rays. In fact most of the materials usable for the envelopes of aerofoils may be penetrated by activating rays if a proper choice of such rays is made. The luminescent materials can not only be activated by ultra violet rays, but also by radium or X-rays and many others. If'radium is used for activation a powdered compound or ore containing radium maybe mixed with the paint which also applies the luminescent material to the aerofo l surface, thus eliminating any electrically energized activating means, and further elim nating any problemof penetratingthe skin or envelope of the aerofoil.

However,--i-t s possible without exposing an ultra violet actuator to the-air stream traversing the aerofoil, to energize luminescent material on the surface of an envelope which is impervious to 'ultra violet. One manner of accomplishing this is shown'in Fig. 5 wherein an ultra violet lamp I'I ismounted within -the fuselage l and directed outwardly through a "window I8 of material readily permeable by ultra violet rays, the arrangement being such that the source thus housed within the aerofoil surfaces of fuselage 'I activates the symbols I 6 paintedin fluorescent 'or phosphorescent materialiupon e in It will, of course, beunderstood that the three types of activation herein suggested may be used interchangeably or concurrently, as desired. In the event that definite symbols such as those indicated at I6 in Fig. 5-are-to be rendered luminescent by the use of'tube generators such as those shown at II inFig. 1, it is important that little or no visible light beemitted by the tubes I I in such a manner as to be apparent from the standpoint of a spectator. It will be found that many conventional wing coverings, including the usual doped fabric, will serve as filters to intercept the visible lightwhile permitting the ultra 'violet radiation to pass through fortheactiVation of the luminescent materialion thesurface.

it is phosphorescent, ishereinafter generically,.

called luminescent.

Fig. 3 shows the same brackets III and activating tubes II within, and a comparable luminescent coating at I5 applied .to the under surface of, the fuselage portion "I of an aeroplane. It will, of course, be understood that the surfaces thus rendered luminescent may include all of the surfaces of the aircraft or may be limited to upper surfaces or lower surfaces or parts thereof. By

switching the activating tubes onor off, the opa' I claim:

1. An aircraft comprising a member provided with a surface skin and a hollow behind said skin, a luminescent material on the surface, and means behind-said'skinf-for generating an activating raybywhichsaid skin is permeable.

I 2. In an aircraft having a-hollow interior and an aerofoil surface'provided with a skin, a luminescent material on the exterior surface of the skin, and means housed within the hollow interior of the aircraft for d irecting activating rays upon such material to render such materia-lluminescent.

3. The combination with an aeroplane wing having a hollow interiorand'a covering skin, of

a luminescent material on the external surface of said skin-and a cool source-of rays-for the activation of such material disposed within the hollow interior of said wing, said skin being permeable to said rays.

4. The combination with an aeroplane wing having a hollow interior and a covering skin, of a luminescent material on the external surface of said skin and a 0001 source of rays for the activation'of such material disposed within the hollow interior of said Wing, said skin being permeable to said rays and said source comprising a lamp type ultra violet generator, said skin being adapted measurably to filter rays of visible light from the discharge of such generator while permitting the passage of ultra violet rays in quantities sufiicient to activate said material.

"5. An aeroplane comprising a wing provided on its lower surfacewith an area of symbolic form provided with a luminescent coating and means for activating said coating comprising a cool operating vapor lamp housed within the wing and giving off activating rays by which the wing is permeable.

6. An aeroplane comprising a wing provided on its lower surface with an area of symbolic form provided with a luminescent coating, and means for activating said coating said aeroplane comprising a fuselage in which said activating means is housed, said activating meansbeing directed through oneside of the fuselage upon the area of the wing which is coated with luminescent material.

7. An aeroplane having an exposed surface directly coated exteriorly with luminescent material and a wholly enclosed means for activatin such material.

8. The article of claim 7 in which said means is electrically energized for activating said material,

material is coated either luminescent or non-luminescent as desired.

9. As a new article of manufacture, an aeroplane having an aerofoil of which at least a substantial area of its entire exterior surface is coated with a material luminescent when activated,

,said aerofoil being provided with a ray generator for activating such material, whereby to render 

